Conventional refractive lenses refract light at the surfaces of a bulk material, such as glass, in order to bend and light. For any single conventional refractive optic there are at least two surfaces in which refraction occurs. Between the surfaces is bulk material, the thickness of the bulk material dependent, in part, on the shape of the two surfaces. Fresnel optics reduce the amount of bulk material by dividing the lens surface into concentric annular sections, and corresponding stepwise discontinuities, between the sections, such that the lens shape is maintained at reduced thickness. Generally, the more annular sections, the thinner the Fresnel lens. This application relates to another approach.